Field of the Invention
The present invention relates to a display device.
Description of the Related Art
A display panel such as a liquid crystal panel and an organic electroluminescence (EL) panel is provided with display elements such as liquid crystals or organic light-emitting elements between two glass substrates on which thin-film devices have been formed.
An image display device equipped with the display panel is configured such that a metal case in which the display panel is accommodated or to which it is adhesively bonded is disposed on a side opposite that of the display surface, and the display surface side is covered with a metal frame.
An image display device in which a display panel is a liquid crystal panel is provided with the liquid crystal panel, a backlight irradiating the liquid crystal panel, and an optical sheet condensing the light from the backlight. Those members are disposed in the order of the optical sheet and the backlight at the back surface side of the liquid crystal panel. A panel holder made from a resin is disposed such as to cover the circumference of the liquid crystal panel and the back surface on the outside of the display region with the object of maintaining a constant space between the liquid crystal panel and the optical sheet and also to hold the liquid crystal panel itself. Further, a metal frame is disposed on the front surface side of the liquid crystal panel. The liquid crystal panel is sandwiched between the panel holder and the frame, with elastic bodies such as cushions being interposed therebetween.
The structure of an image display device will be explained hereinbelow using FIG. 16 that depicts an image display device provided with a liquid crystal panel.
When a display panel 20 is a liquid crystal panel, the display panel is constituted by glass substrates having thin-film devices formed thereon, such as a color filter substrate 20a and a TFT substrate 20b. The display panel 20 is obtained by cutting a large mother glass substrate in a state in which those substrates are sealed. Since the cutting is performed by scribing and breaking by using a diamond cutter, a burr 20c appears on the end surface of the glass substrate. Since the display device such as an organic EL is also configured of a glass substrate, the following phenomenon can occur.
When the image display device is disposed vertically, the lower end of the display panel 20 comes into contact with a panel support section 30a that supports the lower end of the display panel 20 in the panel holder 30. In this case, the lower end of the display panel 20 is sometimes caught by the panel support section 30a under the effect of the weight of the display panel 20 and the burr 20c. The display panel 20 can move on the panel holder 30 for various reasons such as impacts and outer forces occurring when the image display panel is transported. Where the display panel 20 moves, the positional relationship with the cushion changes, a local force can be applied to the display panel 20, the display panel 20 can be deformed, and local stresses can be generated therein. When the aforementioned catching occurs, the display panel 20 that has moved sometimes cannot return to the original position preceding the movement because the display panel has been caught, and the display panel 20 remains in the deformed state. Further, with certain methods for processing the display panel 20, a high friction coefficient can be realized between the end surface of the display panel 20 and the panel support section 30a, even when the burr is not present, and the friction can result in catching. The stresses caused by the catching cannot be removed unless the catching is eliminated.
In a liquid crystal panel, the stresses disturb the orientation of liquid crystals and the application of voltage cannot be accurately controlled. As a result, brightness uniformity and chromaticity uniformity of the displayed image locally decreases at a location where the stresses have appeared in the display panel 20. Such lack of uniformity is called “display unevenness”. The display unevenness can occur close to the panel support section 30a because the burr 20c of the display panel 20 is caught by the panel support section 30a, as mentioned hereinabove. The display unevenness also occurs at other positions when stresses are locally concentrated. A structure that temporarily reduces the stresses applied to the display panel has been suggested to avoid the above-described problems (Japanese Patent Application Publication No. 2010-204357).